Question

A student receives a solution of 2.750 M NaOH to titrate with 12.00 mL of an unknown solution of HCl. The titration requires 19.50 mL. What is the Molarity of the unknown solution of HCl? M

Answer 1

4.46875 M.

Step-by-step explanation:

Equation of the reaction

NaOH + HCl --> NaCl + H2O

Molar concentration = number of moles/volume

Number of moles = 2.75 × 0.0195

= 0.0536 mol

By stoichiometry, 1 mole of HCl reacted with 1 mole of NaOH.

Therefore,

Number of moles of HCl = 0.0536 mol.

Molar concentration in 12 ml = 0.0536/0.012

= 4.46876 M.

Answer 2

1.692 M is the molarity of the unknown solution of HCl.

Step-by-step explanation:

`HCl+NaOH\rightarrow NaCl+H_2O`

To calculate the concentration of acid, we use the equation given by neutralization reaction:

`n_1M_1V_1=n_2M_2V_2`

where,

`n_1,M_1\text{ and }V_1` are the n-factor, molarity and volume of acid which is
`HCL`

`n_2,M_2\text{ and }V_2` are the n-factor, molarity and volume of base which is NaOH.

We are given:

`n_1=1\\M_1=?\\V_1=19.50 mL\\n_2=1\\M_2=2.750 M\\V_2=12.00 mL`

Putting values in above equation, we get:

`M_1=(n_2M_2V_2)/(n_1V_1)`

`=(1* 2.750 M* 12.00 mL)/(1* 19.50 mL)`

`M_1=1.692 M`

1.692 M is the molarity of the unknown solution of HCl.